What your opt-in rate may be costing you
Enter your figures, adjust the assumptions, read a range. Everything runs in your browser: nothing is sent, nothing is stored, no account required.
A parametric estimate, not a measurement
This calculator measures nothing. It applies industry coefficients to figures you type in. Change a coefficient and the result changes — that is the point, and it is why every one of them is shown and editable below. The one number ConsentLift actually measures is your opt-in rate, from the banners genuinely shown on your site.
Conservative → aggressive range. An honest estimate is a range: a single figure would imply a precision that does not exist.
Ghost conversions
measurement gap, not added inThese sales did happen and you were paid for them: they are missing from the ad platform's report, not from your bank account. Adding them to a "loss" would double-count. They are shown because they explain why your acquisition cost looks worse than it is — and why a campaign that was working sometimes gets cut.
Your figures
Rough orders of magnitude are enough. None of these values leave your browser.
How many times your consent banner is displayed in a month, bots excluded.
The share of those banners that end in advertising cookies being accepted. This is the one value ConsentLift measures for you.
The conversions your ad platforms report back. Not your total sales: the ones they claim.
Everything you spend on paid acquisition in a month.
The revenue your platforms tie to those attributed conversions.
The average amount of a single order.
The share of visitors who buy, across all sources.
The assumptions — all editable
These are what make the result. Each is shown with its default value and where it comes from, and you can change it. A calculator that hides its assumptions is worth less than no calculator.
Cart abandonment rate
The share of visitors who fill a cart without buying. The higher it is, the larger the retargeting audience lost.
Source : Baymard Institute — rolling study, 49 sources, 70% observed average.
Retargeting multiplier
How many times better a retargeting audience converts compared with cold traffic.
Source : E-commerce sector average (Criteo Performance Benchmark).
Algorithm degradation coefficient
How much a shortage of conversion signal degrades platform optimisation. The effect stays capped at 50% of spend whatever value you enter.
Source : Calibrated on the performance drop observed after iOS 14.5 (Adjust, AppsFlyer, Branch, 2021-2023), carried over to web consent. It is the most debatable of the three.
Ghost conversion correction factor
An assumption about how well visitors who refuse convert: 0.5 = half as often as those who accept, 1 = just as often.
Source : IAB Europe — TCF Transparency and Consent Framework, 2023 usage report.
The formulas, in full
Three distinct losses, three formulas. None is a black box: if a figure surprises you, it should be reproducible by hand.
Retargeting made impossible
A direct loss, counted in the range.
loss = banners × (1 − opt_in) × cart_abandonment × conversion_rate × retargeting_multiplier × average_order_value
A visitor who abandons a cart but refuses advertising cookies can no longer be shown a reminder ad. The revenue they would have generated on retargeting is mechanically lost. This is the most tangible of the three.
Source : Baymard Institute (cart abandonment), Criteo Performance Benchmark (multiplier).
Algorithm degradation
An indirect loss, counted in the range. Capped at 50% of spend.
waste = ad_spend × min(0.5, coefficient × (1 − opt_in))
Today's bidding algorithms (Advantage+, Performance Max) depend on conversion feedback to optimise. Below a certain signal threshold, optimisation turns approximate and acquisition cost drifts. This is the least visible and most contestable loss — the 50% cap exists to stop the formula producing absurd figures at very low opt-in rates.
Source : Post-iOS 14.5 studies (Adjust, AppsFlyer, Branch) carried over to web consent.
Ghost conversions
A measurement gap. Shown separately, never added to the loss.
ghosts = (attributed_conversions ÷ opt_in − attributed_conversions) × correction_factor
When a visitor refuses advertising cookies, their conversion still happens but no longer shows in the platform's reports. You believe you convert less than you do, you overstate your acquisition cost, and you may cut a campaign that was profitable. This is a steering problem, not a hole in the till.
Source : IAB Europe — TCF Transparency and Consent Framework, 2023 usage report.
The one number that is actually measured is your opt-in rate
Everything above starts from an assumption. Your opt-in rate does not: ConsentLift measures it on the banners genuinely shown, bots excluded, by page, device, country and source — and alerts you when it drops. It installs in minutes on top of your existing CMP.